Emergent Kondo Behavior from Gauge Fluctuations in Spin Liquids.

The Kondo effect is a prominent quantum phenomenon describing the many-body screening of a local magnetic impurity. Here, we reveal a new type of nonmagnetic Kondo behavior generated by gauge fluctuations in strongly correlated baths. We show that a nonmagnetic bond defect not only introduces the potential scattering but also locally enhances the gauge fluctuations. The local gauge fluctuations further mediate a pseudospin exchange interaction that produces an asymmetric Kondo fixed point in low energy. The gauge-fluctuation-induced Kondo phenomena do not exhibit the characteristic resistivity behavior of the conventional Kondo effect, but display a nonmonotonous temperature dependence of thermal conductivity as well as an anisotropic pseudospin correlation. Moreover, with its origin from gauge fluctuations, the Kondo features can be regarded as promising indicators for identifying quantum spin liquids. Our work advances fundamental knowledge of novel Kondo phenomena in strongly correlated systems, which have no counterparts in thermal baths within the single-particle description.